1. Field of the Invention
The present invention generally relates to vehicle power seat adjusters, and more particularly to a drive nut device having an integral drive nut incorporated therein for use in vehicle power seat adjusters.
2. Description of the Related Art
Power seat adjusters are a popular component in many automotive vehicles. Such power seat adjusters provide powered horizontal fore and aft adjustment of the vehicle seat. It is also known to provide vehicle power seat adjusters with a vertical or elevation drive mechanism to elevate and lower the seat height as a whole. Separate front and rear seat elevation mechanisms have also been provided to independently as well as simultaneously adjust the elevation of the front and rear edges of a vehicle seat. Power seat recliners have also been incorporated into a vehicle power seat adjuster.
Typically, a vehicle power seat adjuster includes an upper support frame or support members which engage and support the seat bottom of a vehicle seat. The upper support members are mounted on first and second, spaced track assemblies, each formed of an upper track which is connected to the supper support members and which is also slidable mounted in a lower track fixedly anchored to the vehicle floor.
A drive mechanism, typically formed of a bi-directional electric motor mounted between the first and second track assemblies, rotates a pair of drive shafts extending outward from the motor to a separate gear assembly or gearbox mounted on each upper track. The gearbox is connected to a threaded lead screw extending longitudinally between each upper and lower track pair. A drive block or drive nut is fixedly connected to one of the lower or upper tracks threadingly receives the lead screw to effect reciprocal movement of the upper track and the attached upper seat support member upon selective directional energization of the drive motor.
A similar drive motor, gearbox, and threaded lead screw drive has also been utilized for vertical movement of the front and back ends of the upper support members as well as for pivotal movement of the seat back with respect to the seat bottom.
In such vertical drive mechanisms, the drive nut is typically in the form of a cylindrical, metal, tubular member having an internal threaded bore which receives the lead screw. Outwardly extending lugs are carried on one end of the tubular member and pivotally engage apertures or slots formed in a pair of brackets fixedly extending from a torsion tube or bar rotatably mounted between the front or rear ends of the track assemblies. In this manner, rotation of the lead screw causes linear translation of the drive nut which is converted by the drive nut and the mounting brackets into rotation of the torsion tube. Motion links attached to the torsion tube and the seat support member of frame effect vertical elevation or lowering of the front or rear end of the seat support member or frame.
However, the mounting or formation of the lugs on the cylindrical drive nut as well as the precise mounting and configuration of the torsion tube bracket(s), as well as the precise mounting of the drive nut in systems using a fixed drive nut/torsion tube assembly requires close manufacturing tolerances for proper operation.
For example, U.S. Pat. No. 5,797,574 issued Aug. 25, 1998 to Brooks et al. teaches a drive nut device for a vehicle seat adjuster comprising an elongated strap holding a threaded block drive nut.
U.S. Pat. No. 5,769,377 issued Jun. 23, 1998 to Gauger teaches a six way power seat adjustment apparatus using known block type threaded drive nuts mounted in separate holding brackets.
U.S. Pat. No. 5,467,957 issued Nov. 21, 1995 to Gauger teaches an eight way power seat adjustment apparatus using known block type threaded drive nuts mounted in separate holding brackets.
U.S. Pat. No. 5,172,601 issued Dec. 22, 1992 to Siegrist et al. teaches a drive nut having a generally tubular threaded body with a pair of opposing lugs thereon. The lugged tubular threaded drive nut is mounted in a bracket separately formed and separately attached to a seat slide frame member.
U.S. Patent Application Publication Number 2003/0106978 published Jun. 12, 2003 to Garrido teaches a drive nut for mounting in a separate mounting structure both the drive nut and mounting structure having complimentary shapes.
Thus, it would be desirable to provide a drive apparatus for a vehicle power seat adjuster which overcomes certain of the problems encountered with previously devised drive mechanisms. It would also be desirable to provide a drive nut device for a vehicle power seat adjuster which eliminates the need to mount fixedly the drive nut to separate bracket or torsion tube, thereby simplifying the construction, lowering costs, and providing for easy installation in a power seat adjuster.